ESO’s Very Large Telescope (VLT) has
captured a magnificent face-on view of the barred spiral galaxy Messier
77. The image does justice to the galaxy’s beauty, showcasing its
glittering arms criss-crossed with dust lanes — but it fails to betray
Messier 77’s turbulent nature.

This picturesque spiral galaxy appears to be tranquil, but there is
more to it than meets the eye. Messier 77 (also known as NGC 1068) is
one of the closest active galaxies,
which are some of the most energetic and spectacular objects in the
Universe. Their nuclei are often bright enough to outshine the whole of
the rest of the galaxy. Active galaxies are among the brightest objects
in the Universe and emit light at most, if not all, wavelengths, from
gamma rays and X-rays all the way to microwaves and radiowaves. Messier
77 is further classified as a Type II Seyfert galaxy, characterised by being particularly bright at infrared wavelengths.

This impressive luminosity is caused by intense radiation blasting out from a central engine — the accretion disc surrounding a supermassive black hole.
Material that falls towards the black hole is compressed and heated up
to incredible temperatures, causing it to radiate a tremendous amount of
energy. This accretion disc is thought to be enshrouded by thick
doughnut-shaped structure of gas and dust, called a “torus”.
Observations of Messier 77 back in 2003 were the first to resolve such a
structure using the powerful VLT Interferometer (eso0319).

This image of Messier 77 was taken in four different wavelength bands represented by blue, red, violet and pink (hydrogen-alpha)
colours. Each wavelength brings out a different quality: for example,
the pinkish hydrogen-alpha highlights the hotter and younger stars
forming in the spiral arms, while in red are the fine, thread-like filamentary structures in the gas surrounding Messier 77 [1]. A foreground Milky Way star is also seen beside the galaxy centre, displaying tell-tale diffraction spikes.
Additionally, many more distant galaxies are visible; sitting at the
outskirts of the spiral arms, they appear tiny and delicate compared to
the colossal active galaxy .

Located 47 million light-years away in the constellation of Cetus (The Sea Monster), Messier 77 is one of the most remote galaxies of the Messier catalogue. Initially, Messier believed that the highly luminous object he saw through his telescope was a cluster of stars,
but as technology progressed its true status as a galaxy was realised.
At approximately 100 000 light-years across, Messier 77 is also one of
largest galaxies in the Messier catalogue — so massive that its gravity
causes other nearby galaxies to twist and become warped (eso1707) [2] .

[1] Similar red filaments are also found inNGC 1275.
They are cool, despite being surrounded by a very hot gas at around 50
million degrees Celsius. The filaments are suspended in a magnetic field
which maintains their structure and demonstrates how energy from the
central black hole is transferred to the surrounding gas.

[2]NGC 1055 is located about 60 million light-years away. It is an edge-on galaxy,
in contrast to Messier 77. This Astronomy Picture of the Day portrays
both of them together, in a field of view about the size of the Moon (APOD).

More information

ESO is the foremost intergovernmental
astronomy organisation in Europe and the world’s most productive
ground-based astronomical observatory by far. It is supported by 16
countries: Austria, Belgium, Brazil, the Czech Republic, Denmark,
France, Finland, Germany, Italy, the Netherlands, Poland, Portugal,
Spain, Sweden, Switzerland and the United Kingdom, along with the host
state of Chile. ESO carries out an ambitious programme focused on the
design, construction and operation of powerful ground-based observing
facilities enabling astronomers to make important scientific
discoveries. ESO also plays a leading role in promoting and organising
cooperation in astronomical research. ESO operates three unique
world-class observing sites in Chile: La Silla, Paranal and Chajnantor.
At Paranal, ESO operates the Very Large Telescope and its world-leading
Very Large Telescope Interferometer as well as two survey telescopes,
VISTA working in the infrared and the visible-light VLT Survey
Telescope. ESO is also a major partner in two facilities on Chajnantor,
APEX and ALMA, the largest astronomical project in existence. And on
Cerro Armazones, close to Paranal, ESO is building the 39-metre
Extremely Large Telescope, the ELT, which will become “the world’s
biggest eye on the sky”.